Parameters Design And Simulation On Pixel Circuit For Poly-Si TFT AMOLED Displays

In the information society, people would face various manifestation facilities. Organic Light-Emitting Device(OLED) as one of the new flat panel Display technique, has already obtained the deep concern of science field and the industry field. It has the characteristics of high brightness, high contrast, breadth angle of view, the easy color turn, giving out light high efficiently, high dependability, high speed of response etc. So it drives flat panel display field with the great and earnest hope.The drive ways of OLED can be divided into the Passive Matrix and the Active Matrix. The manufacture process technique of PMOLED is easier than that of AMOLED, The excellent advantage that PMOLED is the price, but compared with the sacrifice on the function, the "cheap" price can't make it attract people. In AMOLED each pixel has two or more TFTs, used to drive the OLED, in order to make the OLED work in the whole frame period. The TFT applied in the AMOLED is mainly divided into the Poly-Si TFT and the a-Si TFT. The a-Si TFT has the simple craft of manufacture. Along with the development of the TFT-OLED, the weakness of the a-Si TFT becomes sharp gradually, polysilicon have more advantages than it.Much work of this paper has been done in Poly-Si TFT AMOLED technology, mainly focus on parameters assurance of 2-TFT pixel circuit and mirrored pixel circuit for driving AMOLED, and simulation work on these kinds of pixel circuit using Star-Hspice. The main work and content are sumed up as follows:Chapter 1 describes the development history and the present status of the OLED technique, points out that the OLED technique offers a promising avenue, and will be used widely in future. I depict the characteristics and structures of OLED, and the method of achieving full color display. I subsequently introduce the two kinds of driving technique of OLED, gives the advantages of AMOLED by comparing it with PMOLED.In chapter 2, at first, I compare Poly-Si TFT and a-Si TFT, enumerate the advantages of Poly-Si TFT AMOLED. Subsequently, I introduce the craft flow of Poly-Si TFT, and the basic structure of the driving circuit for AMOLED. In addition, I introduce the Level62 RPI Poly-Si TFT model and its characteristics, because thin-film transistor is main component of driving circuit which I concern. At last I simulate the work of the single TFT with Level62 RPI Poly-Si TFT model using Star-Hspice, and analysis the kink effect.Chapter 3 is the core of this paper, the research focus on the parameters assurance and simulation of driving circuit for Poly-Si TFT AMOLED. The main work is based on the design rules for polysilicon of Korean company of PT-PLUS Company in Korea, the related design rules, the craft document and working current of OLED, I ensure the parameters of the 2-TFT pixel circuit and the mirrored pixel circuit and simulate the pixel circuit with the parameters.For the 2-TFT pixel circuit, at first, I analysis the working principle, and select the models of single devices. According to the working condition that 96×3×128 pixels array and the refresh rate of 60HZ, I calculate the driving signal. Subsequently, I simulate the working of the 2-TFT pixel circuit, analysis the influence to the result caused by variety of parameters, then modify and optimize the device parameters. At last, I ensure the parameters of 2-TFT pixel circuit: (W/L)_T1=10u/10u,(W/L)_T2=30u/10u,C_S=0.8pF.For the mirrored pixel circuit, in the beginning, I also analysis the working principle of the pixel circuit detailedly, consider the working condition and parasitical effect, I calculate the parameters of single devices. Subsequently, I simulate the working of the whole pixel circuit, according to the simulation result, I make sure that the difference between I_oled and Idata is caused by kink effect and change injection effect. I also analysis the effect to the I_oled caused by variety of (W/L)_T2,C_S,V_th, compared with 2-TFT pixel circuit, mirrored pixel circuit can avoid the luminance nonuniformity caused by variety of V_th. In order to solve the problems of mirrored pixel circuit, I optimize the circuit structure, simulation results indicate that performance of the optimized structure is improved. At last, make sure the parameters of optimized mirrored pixel circuit: (W/L)_T1=10u/10u,(W/L)_T2=10u/10u,(W/L)_T3=20u/10u ,(W/L)_T4=20u/10u, C_S=5pF。...